The purpose of this project is to conduct research in statistical methods and computer techniques with particular emphasis on those appropriate to the analysis of data from clinical and diagnostic trials and epidemiological studies of cancer. Many of the problems studied under this project arise from the consultative activities of the Section. In the past year this research has included new work on sample size determinations for clinical trials, studies of sequential survival analysis, methodological and computational work on time-dependent covariate analysis appropriate for studying the effects of serial tumor markers and other sequentially recorded covariate information, a study of tests of equality of two proportions in 2x2 tables, and a study of multiple comparisons in two-way tables which may help interpret results of subset analyses commonly encountered in epidemiologic and clinical studies.